Field of the Invention
The present invention relates to a power generation apparatus and a power generation system.
Description of the Related Art
Hitherto, there is known a power generation apparatus that drives an expander by a working medium and generates power by a generator directly coupled to the expander. A power generation apparatus disclosed in JP 2004-353571 A is equipped with a cooling pipe that leads a working medium condensed by a condenser to a cooler of a generator. Accordingly, the generator may be effectively cooled. However, a problem arises in that the cooling pipe that leads the working medium to the cooler of the generator is needed. On the contrary, a power generation apparatus disclosed in JP 2012-147567 A may cool a generator without providing a cooling pipe. That is, in the power generation apparatus, the expander and the generator are accommodated inside a casing, and the casing is provided with a partition wall portion that divides the casing into a first space accommodating the expander and a second space accommodating the generator. Then, the partition wall portion is provided with a communication portion that causes the first space to communicate with the second space. The communication portion extends from a discharge port, from which the working medium expanded by the expander is discharged, toward the second space. Accordingly, the working medium that is expanded by the expander inside the first space is introduced into the second space through the communication portion. Although the second space accommodates the generator, a working medium discharge portion is provided at the opposite side to the communication portion with the generator interposed therebetween. For this reason, the working medium that is introduced into the second space through the communication portion passes through the inside of the generator (for example, a gap between a stator and a rotor), and is discharged from the discharge portion to the outside of the casing.
In the power generation apparatus disclosed in JP 2012-147567 A, the generator may be cooled without providing the cooling pipe, but the following problems remain. That is, in the power generation apparatus, since the working medium is caused to pass through the inside of the generator (for example, the gap between the stator and the rotor), the working medium circulation resistance increases, and hence a problem arises in that the power generation efficiency is degraded. Further, if the working medium contains foreign matter, a problem also arises in that the foreign matter intrudes into the gap between the rotor and the stator of the generator.